Follow Upgrade Nuxeo and apply the following procedure before starting Nuxeo.
While upgrading from 5.1.2 to 5.1.3, you may have to manage with a Blob format issue : that means to patch $JBOSS/server/default/data/NXRuntime/repos/default/repository/nodetypes/custom_nodetypes.xml Take this file, format it with tidy (tidy -wrap 999 -indent -xml) and apply this patch (manually as it can't guarantee any line numbers; add the lines beginning with a "+" if not already present):
+ <nodeType hasOrderableChildNodes="false" isMixin="true" name="ecmmix:content" primaryItemName="">
+ <propertyDefinition autoCreated="false" mandatory="false" multiple="false" name="digest" onParentVersion="COPY" protected="false" requiredType="String" />
+ <propertyDefinition autoCreated="false" mandatory="false" multiple="false" name="length" onParentVersion="COPY" protected="false" requiredType="Long" />
+ <propertyDefinition autoCreated="false" mandatory="false" multiple="false" name="filename" onParentVersion="COPY" protected="false" requiredType="String" />
+ </nodeType>
<nodeType hasOrderableChildNodes="false" isMixin="false" name="ecmft:content" primaryItemName="">
<supertypes>
<supertype>ecmnt:property</supertype>
+ <supertype>ecmmix:content</supertype>
+ <supertype>nt:resource</supertype>
</supertypes>
<propertyDefinition autoCreated="false" mandatory="false" multiple="false" name="mime-type" onParentVersion="COPY" protected="false" requiredType="String" />
<propertyDefinition autoCreated="false" mandatory="false" multiple="false" name="data" onParentVersion="COPY" protected="false" requiredType="Binary" />
<propertyDefinition autoCreated="false" mandatory="false" multiple="false" name="encoding" onParentVersion="COPY" protected="false" requiredType="String" />
</nodeType>
Then, you need to re-index your data. Using nuxeo-shell (versus web function in advanced search) is recommended.
Another solution (than patching custom_nodetypes.xml file) is to export then re-import data before and after the upgrade (using nuxeo-shell too); but this method will make you loose versioning information.